A large number of clinical trials have demonstrated that anti-coagulant drugs, such as Warfarin, are highly effective at preventing strokes and heart attacks in at-risk population groups. However, these drugs can cause uncontrolled bleeding and other undesirable side effects. Thus, frequent monitoring of blood coagulation rates by prothrombin time tests is required for safe treatment. This requires the patient to visit a clinic every few weeks for testing, at considerable expense and inconvenience. The availability of a simple, accurate, low cost home test would facilitate wider use of anti-coagulant treatments and potentially improve the standard of care for anticoagulated patients. Avocet's phase I grant application proposed to develop such a test by incorporating fluorescent thrombin substrate technology into a simple, dry reagent test strip to produce a low cost strip/meter system similar to the home blood glucose systems widely used by diabetics. This approach was successful, and working prototypes were produced. In phase II, the studies will continue, and focus on: optimization of the test strip and meter, scale-up issues, calibration, human factors studies, control solution development, and extensive clinical trials. The studies, together with Phase III studies, will be used to seek FDA certification of the system.